1. Field of Invention
The current invention relates generally to apparatus, systems and methods for amplifying a signal. More particularly, the apparatus, systems and methods relate to amplifying a radio frequency (RF) power signal. Specifically, the apparatus, systems and methods provide for a power amplifier that uses multiple cascode amplifiers some of which are grouped together and some of which are spaced apart.
2. Description of Related Art
Amplifiers have long been used to amplify a variety of electrical signals. For example, amplifiers can be used to amplify voltage, current, power and the like. Early amplifiers used vacuum tubes to amplify signals. These tubes where large, used high power and often burned out. The invention of the silicon transistor greatly improved amplifier technology and quickly led to the extinction of vacuum tubes. Silicon transistors were much smaller, cheaper, could be more easily mass produced and had a much longer life span than vacuum tubes. Additionally, transistors consume much less power and generate less heat than vacuum tubes.
Because of a transistors small size, it has allowed for more sophisticated amplifiers to be designed. For example, operational amplifiers (Op Amps) contain two or more stages of amplification each with their own bias schemes all implemented with transistors and other discrete components. Op Amps provide excellent common mode rejection so that just a signal of interest is amplified.
One conventional approach to amplifying radio frequencies (RF) is to use a cascode amplifier that has a common gate transistor and a common source transistor. However, these types of amplifiers often have a small operational bandwidth (BW) and cannot handle higher currents/power. Therefore, what is needed is a better amplifier.